1. Field of the Invention
The present invention relates to a contactless charging apparatus for a portable terminal. More particularly, the present invention relates to a contactless charging apparatus for a portable terminal that improves durability.
2. Description of the Related Art
A portable terminal is typically charged using a wired charging method. The wired charging method may be divided into a method that uses a USB type charger and a method that uses a holder type charger.
The USB type charger is directly inserted into a charging socket formed at one side of a portable terminal in order to charge the portable terminal.
On the other hand, the holder type charger charges the portable terminal by supplying current to a terminal included in the holder that is connected to a battery terminal of a portable terminal. The other end of the holder terminal is electrically connected to an external outlet.
However, the wired charging method may not properly charge the battery of a portable terminal due to a defective contact between the charger and the battery during the charging period, resulting in an undercharged battery and reduction of battery life.
To address the foregoing problems, a contactless charging method has been developed. The contactless charging method does not charge a portable terminal using a charger in a wired scheme. Rather, the contactless charging method includes a contactless charger and a contactless charging apparatus installed in a portable terminal.
In the contactless charging method, a secondary coil of a contactless charging apparatus that is installed in a portable terminal generates an electromotive force that is induced by a primary coil mounted in a contactless charger to charge a battery located in the portable terminal.
In recently developed contactless charging methods, a secondary coil of a contactless charging apparatus is mounted in a battery or is separately installed in an external contactless charging apparatus of the portable terminal.
In the case where the secondary coil is mounted in the battery, if the battery is lost, the user must but a new battery of the same type since a battery of another standard may not include a secondary coil mounted in the battery and thus may not be charged. However, because a secondary coil is mounted in the battery, the battery is expensive. Accordingly, if the battery reaches its end of life or if the battery is lost, a user must buy a battery with a secondary coil in order to power the portable terminal.
On the other hand, when the secondary coil is installed in a separate external contactless charging apparatus, a thickness of the portable terminal is increased due to a charging component. This results in an inconvenience to the user.
In addition, since secondary coils are wound by a copper line, they are more susceptible to electric shocks and may be easily circuit-shorted. In that case, the portable terminal cannot be charged.